The present invention relates broadly to protective guards for conduit such as hose, tubing, wire, cable, and fiber optics, and more particularly to a moldable, plastic guard segment having a first end adapted to be connected with a mating second end of another guard segment in providing a segmented guard assembly of a variable length.
When conduit such as hose, tubing, wire, cable, or fiber optics is exposed to certain environmental conditions, physical obstacles, or human abuse, the portion of the conduit so exposed may be protected with an external guard or armor. Such guards typically are formed as a coiled steel wire spring or, alternatively, as an elongate plastic or rubber sleeve or spiral. The coil, sleeve, or spiral is configured as having an inner diameter which is sized to be marginally larger than the outer diameter of the wire or conduit to allow the guard to be installed coaxially over the hose or wire. Guards or armor of such type are shown in U.S. Pat. Nos. 5,857,711; 5,816,622; 5,608,963; 5,277,227; 4,967,799; 4,876,810; 4,805,933; 4,446,607; 4,406,852; 3,926,141; and Des. 356,858; and in European Pat. Appln. Nos. 824,205; and 655,377. A plastic guard is manufactured by WABCO (Westinghouse Air Brake Co.) GmbH of Hannover, Germany. Typical applications of guards and coils of such type include the protection of hydraulic hose in construction machinery or plant equipment, and of airbrake tubing coils in tractor trailers rigs and other vehicles. Hoses, tubing, fittings, and other components for these applications are described further in U.S. Pat. Nos. 5,232,645; 4,009,734; and 3,977,440; and in U.K. Pat. Appln. GB 2,239,503. Such components are manufactured commercially by Parker-Hannifin Corporation of Cleveland, Ohio, through its Parflex Division of Ravenna, Ohio, and its Brass Products Division of Otsego, Mich., and by Tectran, Inc., of Mississauga, Ontario, Canada.
Each of the guard types heretofore known in the art offer varying degrees of strain relief and/or cut, crush, abrasion, or kink resistance. In general, steel wire springs offer good kink and abrasion resistance. However, as being formed of a metal, springs are subject to corrosion and are relatively heavy which may impact their use in certain mobile applications. When employed at the connected end of a hose or tubing assembly, the spring conventionally is locked to the end fitting which usually is provided as a multi-component including a body, nut, ferrule, and insert.
Plastic or rubber sleeves or spirals conventionally are manufactured by either extrusion, molding, or spiraling, and are known to be generally lightweight and corrosion resistant. In particular, extruded guards offer long, continuous lengths, but the raw materials suited for extrusion generally are considered to be either too flexible to prevent kinking, or too rigid to prevent flexing of the hose without breaking or kinking the guard absent the addition of strain relief slots. Spiral guards, typically provided as strips of plastic thermoformed about a mandrel into a helical shape, also offer long, variable lengths, but generally do not afford appreciable kink resistance. Molded guards can be formed with the rigidity necessary to prevent kinking, but heretofore have been limited in length to the size of the mold.
In view of the foregoing, it is believed that continued improvements in guard constructions for wire and conduit tubing coil assemblies would be well-received by the transportation, construction, and other industries involved. A preferred construction would be economical to manufacture, but also would afford good abrasion and kink resistance. Such a construction additionally would be corrosion resistant and accommodate variable guard lengths.
The present invention is directed to a protective guard for conduit such as hose, tubing, wire, cable, and fiber optics, and more particularly to a segmented guard assembly which may be varied in length depending upon the number of guard segments connected in series to form the assembly. In accordance with the precepts of the present invention, each of the guard segments which form the assembly is provided as a unit construction having a first end adapted to be coupled with a mating second end of another guard segment.
Such unit construction may be molded of plastic material which may be both corrosion-resistant and lightweight, and further which may be selected to provide sufficient rigidity to prevent kinking and to offer good abrasion resistance. Advantageously, the series connection of the first end of one unit to the second end of an adjacent unit allows a given unit length to cover a range guard lengths while obviating the need and expense of having to mold long, continuous guard lengths or guards of different lengths. The units may be removably joined such as with a threaded engagement, an interference, i.e., xe2x80x9csnapxe2x80x9d fit, or other mechanical method. Alternatively, the units may be permanently bonded using an adhesive, fusion welding, or other bonding method.
When employed, for example, as a point of attachment guard for lengths or coils of tubing or hose such as may be found in hydraulic or airbrake applications, the guard assembly and unit construction thereof of the present invention permits the use of economical, one-piece barbed-type fittings as the end connection for the tubing or hose. In this regard, the distal end of the first guard segment in the series may be interference fit over the hose or tubing end as received over the fitting barb. Such an arrangement eliminates the necessity of the more expensive multi-component fittings heretofore used with spring coil guards.
These and other advantages will be readily apparent to those skilled in the art based upon the disclosure contained herein.